1. Field of the Invention
The present invention relates to a substrate carrying mechanism that supports a substrate that is a carrying subject, a substrate processing apparatus that is equipped with the substrate carrying mechanism, and a semiconductor device manufacturing method that is performed by using the substrate processing apparatus.
2. Description of the Related Art
Generally, substrate processing apparatus used in a semiconductor device manufacturing process are equipped with a processing chamber and a carrying device. The processing chamber processes substrates such as wafers. The carrying device carries the substrates into the processing chamber, and carries the substrates out from the processing chamber. The carrying device is equipped with a substrate carrying mechanism called tweezers. The substrate carrying mechanism supports the substrates that are the carrying subjects. For example, Japanese Patent Application Laid-Open (JP-A) No. 2007-184476 discloses such carrying mechanism. This substrate carrying mechanism is configured such that a stepwise support portion is formed on a two-pronged fork-like plate-like body called a finger plate, and the support portion supports four places in the neighboring portions of the outer peripheral edge of the substrate from the back surface side of a surface of the substrate that undergoes processing.
However, in the substrate carrying mechanism described in JP-A No. 2007-184476, in a case when deformation, such as warping and bending, has occurred in the substrate, the substrate contacts at places outside the support portion, and rubbing occur due to a decrease in the force to hold the substrate by the support portion (frictional force between the substrate and the support portion). Such contact and rubbing may lead to the generation of scratches and particles. Further, when deformation has occurred in the substrate, the contact area between a support member and the substrate decreases, and the substrate holding force decreases. When the substrate holding force decreases, carrying capability of the substrate decreases.